N-methyl-D-aspartate receptor–Postsynaptic density protein 95–Neuronal nitric oxide synthase protein complex (NMDAR–PSD-95–nNOS)

The N-methyl-D-aspartate receptor–Postsynaptic density protein 95–Neuronal nitric oxide synthase (NMDAR–PSD-95–nNOS) complex is a specialized signaling assembly located at the postsynaptic density of glutamatergic synapses. In this complex, the scaffolding protein PSD-95 acts as a bridge, linking the C-terminal tail of the NMDAR GluN2B subunit to the nNOS enzyme through PDZ domain interactions (Aarts et al., 2002, Science). This physical proximity allows for the efficient coupling of NMDAR-mediated calcium influx to the activation of nNOS, which is essential for normal synaptic plasticity but becomes pathological during excitotoxic events like ischemic stroke. When overactivated, the complex generates excessive nitric oxide and reactive oxygen species, leading to neuronal apoptosis and necrosis (Zhou et al., 2010, Nature Medicine). Therapeutic intervention typically involves the use of decoy peptides or small molecules, such as Nerinetide, designed to disrupt these protein-protein interactions. By uncoupling the receptor from the downstream toxic signaling pathway, these drugs aim to provide neuroprotection without the adverse effects associated with direct NMDAR channel blockade (Hill et al., 2020, Lancet). This approach represents a shift from traditional receptor antagonism to targeted disruption of pathological signaling hubs (Doucet et al., 2012, Front Cell Neurosci).

Other names

NMDAR-PSD95-nNOS ternary complexGluN2B-PSD95-nNOS complexExcitotoxic signaling complexNMDAR-PSD95-nNOS signaling hub

Disruption of protein-protein interactions (PPI) between the NMDAR GluN2B subunit and PSD-95, or between PSD-95 and nNOS, to decouple calcium influx from toxic nitric oxide production.